Arc extinguishing structures for circuit interrupters



Feb. 28V, 1967 s. A. BOTTONARI ARC EXT-INGUISHING STRUCTURES FOR CIRCUIT INTERRUPTERS 4 Sheets-Shea?l 1 Filed Aug. 6, 1964 HIV 7 O 4 HIHV w. M I 9 m M NIIII .IIII/QVMI4I WVIIIIIQUIW I l I I I III IIIIIIIJIIIIII I I||||||I|||| f ////////////////f-. A )1., V.III:I IIIIIIIIII Illy!! WM. nm 4 If w 9 l I l I I II lllll II III r d .m m w l 6 I I I I I I I I I I I I I I I I I IIJ .d B I. i 5 M W Mw M N. nl, I I4 B 3 f\ Fill I I f. 2 3 \\\Mm\\ V 1 4 fm k m 2 mm 8 3 7 3 7/ Ill I i I I I l I I I I I I l I l l l l IIL 'l2 m l M AI- W O l Af m6* ,5 F I I I I I I I I I I|||I I I I I I,\ Q 3 f IIIT I I I I I I I I I I I-I IIL m/ Y 3( Af//////.VrV//// f/f f, //vVf//// I n I HIIUHI- UHHHIHMI II ,IIHIIIIIII HIUIUII H C m L @la w` m m nu@ 1 f FIG. I.

Feb. 28, 1967 s. A. BOTTONARI ARC EXTINGUISHING STRUCTURES FOR CIRCUIT INTERRUPTERS 4 Sheets-Sheet 2 Filed Aug. 6, 1964 ALi.

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WITNESSES Feb. 28, 1967 s. A. BoTToNAm 3,307,004

ARC EXTINGUISHING STRUCTURES FOR CIRCUIT INTERRUPTERS Filed Aug. 6, 1964 4 Sheets-Sheet 5 QA f49 il- /45 O O l 45\. O O |52 Feb. 28, 1967 s, A. BoTToNARl I 3,307,004

ARC EXTINGUISHING STRUCTURES FOR CIRCUIT INTERRUPTERS y Filed Aug. 6, 1964 I 4 Sheets-Sheet 4 -m l 34u 32A r49 32A L| I- I I I 45\ O l /35 3e 37 I I I zij' F |53 wvl' o :D:

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n: n I53 III l I I @Il FIGS /.Lkl 35 (|52 ,49 38\ |34 I 45 f I3I |32 I3 f 1542 ma. 6 '37 United States Patent O 3,307,004 ARC EXTINGUHSHENG STRUCTURES FOR ClRClUI'I INTERRUPTERS Samuel A. Bottonari, Williinsburg, lla., assignor to Westinghouse Electric Qorporation, Pittsburgh, la., a corporation of Pennsylvania Filed Aug. 6, 1954, Ser. No. 387,919 Claims. (Cl. 20G- 144) This invention relates to circuit interrupters and more particularly to arcextinguishing structures for circuit interrupters.

In certain types of known circuit interrupters, the circuit interrupter construction includes contact means operable .to establish an arc which is moved into an arcchute structure in which an arc-extinguishing means is disposed. In order to withstand the thermal conditions which result when an arc is established between the contact means of the circuit interrupter, the arc-chute of the circuit interrupter may include an arc shield or fire plate adjacent to the arc-extinguishing means which is disposed inside the arc-chute. It is desirable to provide an improved arc-chute construction including arc-extinguishing means which offers all of the advantages of a conventional arc-chute structure of the type which includes an arc shield or re plate and which offers several additional advantages.

It is an object of this invention to provide a new and improved means for extinguishing the arc in a circuit interrupter.

A more specific object of this invention is to provide a new and improved arc-chute construction for circuit interrupters.

Another object of this invention is to provide an improved means for increasing the mobility of the arc during the operation :of a circuit Iinterrupter.

A further object of this invention is to provide `an improved means for lengthening the arc established more quickly during the operation of a circuit interrupter.

Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description, taken in conjunction with `the accompanying drawing, in which:

FIGURE 1 is a side elevational view, partially in section, of a circuit interrupter embodying the pr-inciples of the invention with the contact structure of the interrupter being shown in the closed circuit position;

FIG. 2 is a plan sectional view of the circuit interrupter shown in FIG. 1, taken along the line II-II of FIG. l;

FIG. 3 is a side elevational view illustrating the exterior of one section or portion of the housing of the arc-chute structure of the circuit interrupter shown -in FIG. l;

FIG. 4 is a vertical sectional View of the housing section shown in FIG. 3, taken along the line IV-IV of FIG. 3;

FIG. 5 is a bottom view of the housing section shown in FIG. 3;

FIG. `6 is a side elevational View, illustrating the interior of the housing section shown in FIG. 3;

FIG. 7 is an elevational end view of the housing section shown in FIG. 6, taken along the line VlI-ViI in FIG. 6; and

FIG. 8 is a plan sectional View of the housing sect-ion shown in FIG 6, taken along the line VIII-VIII of FIG 6.

Referring now to the drawing and to FIGS. 1 and 2 in particular, there is shown a circuit interrupter, more specitically a circuit breaker 10 embodying the teachings of the invention. In this instance, the circuit interrupter or breaker 10 is illustrated as being of the air-break type although it is to be understood that certain features of the invention may be applicable to other types of circuit interrupters, such as those of the liquid-immersed type or those operating in a gaseous medium, such as sulfur hexauoride.

In general, the circuit interrupter or breaker 10 includes the contact structure or means 20 which is operable to establish an arc, which is then moved upwardly into an arc-chute structure 30, which includes a pair of arc-extinguishing sections or stacks 22 and 24 of substantially identical construction. The contact means 20 comprises a relatively stationary contact which includes the Contact portions 12A and 12B and a movable contact 14 which engages the stationary contact portions 12A and 12B of the circuit interrupter 10 in the closed circuit position of said linterrupter and which is disposed at the free end of a Contact arm 16 which is rotatable about a lower xed pivot (not shown). The stationary contact portions 12A and 12B are mounted at the outer end of an insulating terminal bushing 18 which may be supported upon an insulating frame 19. One terminal L1 of the interrupter 10 is connected to the stationary contact portions 12A and 12B, while the other terminal L2 of the interrupter is electrically connected to the movable contact arm 16 and to the movable contact 14 of the interrupter.

More specifically the arc-chute structure 30 comprises the insulating housing or jacket which includes the first and second housing Sections 32A and 32B, respectively, in which the rst and second arc-extinguishing sect-ions 22 and 24, respectively, are disposed, the magnetic structure 40, on which the blowout coils or windings 31, 34 are inductively disposed to be energized during an interrupting operation of the circuit interrupter 10 to assist in effecting movement of the arc established between the contacts of the contact means 20 into the arc-extinguishing sections 22 and 24, the center or intermediate arc-horns 82 and 84 which are connected in circuit relation with the blowout coils 31 and 34 respectively, the transfer arc-extinguishing section 60 which facilitates energization of the blowout `coils 31 and 34 during an interrupting operation of the circuit interrupter 10 and the outer arc-horns 92 and 94, which are disposed inside the insulating housing adjacent to the end portions of the housing sections 32A and 32B, as best shown in FIG. 1. Certain features of the -arcchute structure 30 are disclosed and claimed in U.S. Patent 2,692,319 issued October 19, 1954, to Robert C. Dickiuson and Russell E. Frink which is assigned to the same assignee as the present application.

In particular, the housing sections 32A and 32B, which are substantially identical, are preferably formed or molded from a suitable electrically insulating material having adequate mechanical or structural strength, such as glass reinforced polyester resin, with a suitable filler, such as aluminum trihydrate, to give the material excellent anti-tracking `or arc resisting properties. As best shown in FIGS. 2, 6 and 8, each of the housing sections 32A and 32B is generally U-shaped in cross section and in- Icludes a vertically extending side wall portion 49, the end wall portions 41 and 43 which are preferably formed integrally with the ends of the associated side wall portion 49 and which extend laterally toward the side wall portion 49 of the mating housing section, as best shown in FIG. 2, and the ange portions 47 and 4S which are preferably formed integrally with the associa-ted end wall portions 41 and 43, respectively, to project outwardly from said end wall portions in a plane which is generally parallel with the plane of the associated side wall portion 49. When the ange portions 4S and 47 of the housing sections 32A and 32B are assembled together, as best shown in FIG. 2, and secured in assembled relationship -by suitable means, such as the bolts 112, a

generally rectangular arc-chute housing is formed having a generally rectangular opening or passageway therethrough. The flange portions 45 and 47 of the housing sections 32A and 32B include the recesses or slots indicated at 117 and 119, respectively, in FIGS. 1 and 6, which are assembled in mating relationship when the housing sections 32A and 32B are brought together to receive a gasket member 114 las shown in FIG. 2 to prevent the escape lof hot gases which may also be ionized from the ends of the housing sections 32A and 32B during the operation of the circuit interrupter 1i). The gasket member 114 may be formed from a suitable material, such as asbestos rope. The wall portions 49 of the housing sections 32A and 32B include the generally rectangular openings 152 through which the magnetic structure 4i) passes, as shown in FIG. 2. The housing sections 32A and 32B also include the vertically extending rib or raised portions 35, 36, 37 and 38 which are spaced from one another, as best shown in FIG. 6, and which project inwardly from the side wall portion 49 to assist in retaining the arc-extinguishing sections 22 and 24 in proper position or assembled relationship inside the housing sections 32A and 32B during the operation of the circuit interrupter 10. In order to prevent the gas pressure generated within the arc-extinguishing sections 22 and 24 from blowing said sections upwardly out of the arcchute structure 30 during the operation of the circuit interrupter 10, the horizontally ext-ending strip or rib portions 34 are provided at the top of each of the housing sections 32A and 32B, as shown in FIG. 6. The retaining portions 34 through 38 are preferably formed or molded integrally with the associated housing section from the same material.

In order to increase the eiective insulating creepage path adjacent to the arc established by the contact means during the `operation of the circuit interrupter 10, each of the housing sections 32A and 32B includes a plurality of spaced, vertically extending raised or rib portions 131 through 138, as best shown in FIG. 6, which are generally diverging with respect to one another and which extend from a point adjacent the contact means 20 to a point adjacent the arc-extinguishing sections 22 and 24, as shown in FIG. l. The rib or ridge portions 131 through 138 are preferably formed or molded integrally with the side wall portion 49 of the associated housing section and from the same material to project inwardly toward the associated contact means 20 with the valley or recess Iportions 142 between the successive raised portions 131 through 138 defining a plurality of spaced air or gas passageways which permit more air or gas to move in ybehind the arc as it moves upwardly from the contact means 2li toward the arc-extinguishing sections 22 andl 24 to thereby more effectively cool the arc. In addition, the diverging rib or partition portions 131 through 138 serve to enhance or increase the natural mobility or velocity of the arc as it moves upwardly by gradually and more quickly expanding or lengthening the arc radially as well as in a vertical direction.

In order to support and position the transfer arc-extinguishing section `60 between the housing sections 32A and 32B, each of the housing sections 32A and 32B includes a generally rectangular recess 154 with the back wall of the recess being formed by a projecting portion 155 which extends inwardly from the plane of the side wall porti-on `49 of the associated housing section, as best shown in FIG. `6.

In order to rotatively support the housing sections 32A and 32B and the complete arc-chute structure 30, each of the housing sections 32A and 32B includes an integral hinge portion 183 which extends outwardly away from the adjacent end wall portion 41 and which includes a slot 182 adapted to receive a hinge pin 164 which is formed from an electroconductive material and which is supported at its ends by the bracket members or pivot supports 162. The supports 162, in turn, are supported by and secured to the stationary contact portion 12A of the circuit interrupter 10, as best shown in FIG. 1.

The magnetic structure 40 of the arc-chute structure Sti is generally I-I-shaped in cross-section, as shown in FIG. 2. The magnetic structure 40 includes a pair of side pole plates 46 which are disposed on opposite sides of the housing formed by the housing sections 32A and 32B, each of said side pole plates being preferably laminated and formed by assembling a plurality of sheets or strips of soft magnetic material, which are secured together by suitable means, such as rivets. The side pole pla-tes 46 are magnetically interconnected by the interconnecting yoke portion 48 of the magnetic structure 40 which passes through the openings 152 in the h-ousing sections 32A and 32B and which may be secured or bolted to the side pole plates 46 by suitable means, such as the mounting bolts 72, shown in FIG. 2. Each of the side pole plates 46 includes a lower depending portion 47 which exten-ds primarily down below the arc-extinguish ing section 22 which is more remote from the contact means 28 than the arc-extinguishing section 24 in order to more nearly equalize the velocity of movement of the arc establsihed by the contact means 20 into the respective arc-extinguishing sections 22 an-d 24, as explained in detail in the Dickinson et al lpatent previously mentioned. In order to prevent the formation of a conductive path between the center arcing horns 82 and 84 during the operation of the circuit interrupter 10, the insulating washers or members 74 and 75 are interposed between the side pole plates `46 of the magnetic structure 40 and the adjacent side wall portions of the housing sections 32B and 32A adjacent to the sides of said arc horns, as best shown in FIG. 2. The insulating washers 74 and 75 surround the yoke portion 48 of the magnetic core 4t) where the magnetic core 40 passes through the openings 152 of the housing sections 32A and 32B. The side pole plates 46 may also be maintained in assembled relationship with the housing sections 32A and 32B by suitable means, such as the connecting bolts 102 and 104 shown in FIG. 1, which connect the side pole plates 46 above and below the yoke portion 48 of the magnetic structure 40 and pass through the openings 152 in the housing sections 32A and 32B and the blowout coils 31 and 34 to also maintain other portions of the arc-chute structure 30 in assembled relationship.

In order to establish a magnetic iiux in the magnetic structure 4t) during the operation of the circuit interrupter 10 and to assist in effecting upward movement of the arc established by the contact means 20 into the arc-extinguishing sections 22 and 24, the rst and second blowout coils or windings 31 and 34, respectively, are inductively disposed on the yoke portion 48 of the magnetic structure 40, as best shown in FIGS. 1 and 2. The blowout coils 31 and 34 which are spaced from one another along the yoke portion 48 of the magnetic structure 40 and disposed adjacent to the side wall portions 49 of the associated housing sections 32B and 32A, respectively, each includes a plurality of insulated conductor turns which are wound around the yoke portion 48 to form a winding which is generally oblong in cross section, as shown in FIG. l. In order to additionally insulate the blowout coils 31 and 34 from the yoke portion 48, an insulating strip member 62 may be wound around the yoke portion 48 between said yoke portion and each blowout coil, as shown in FIGS. l and 2. In order to facilitate energization of the blowout coils 31 and 34 during the operation of the circuit interrupter 10, one end of the blowout coil 31 is electrically connected to the lower curved portion of the center arc horn 82 which is formed from a conducting sheet material and includes 'an upwardly extending portion that is interposed between the blowout coils 31 and 34 and the arc-extinguishing section 22 to serve as an arc-horn for the later arc-extinguishing section. Similarly, one end of the blowout coil 34 is electrically connected to the lower curved portion of the center archorn 84 which also includes an upwardly extending portion that is interposed between the blowout coils 31 and 34 and the arc-extinguishing section 24 to serve as an archorn for the latter arc-extinguishing section. In order to electrically insulate the blowout coils 31 and 34 from the adjacent center or transfer arc-horns S2 and 34, an insulating strip member 33 may be additionally wrapped around the outer periphery of each of said blowout coils, as shown in FIGS. 1 and 2. In order to additionally insulate the blowout coils 31 and 34, the electrically insulating washers 42 and 44 may be disposed on the yoke portion 48 adjacent to the associated blowout coils 31 and 34, respectively, as best shown in FIG. 2. The other ends of the blowout coils 31 and 34 are electrically connected to the terminal spacer members 39, which are formed from `an electrically conducting sheet or strap material, and electrically and mechanically connected together by the conducting bolt means S4, as shown in FIG. 2 to thereby electrically connect the blowout coils 31 and 34 in series circuit relationship between the terminals formed by the center arc-horns 82 and 84.

In order to assist in maintaining the blowout coils 31 and 34 in spaced relationship when said blowout coils are subjected to certain magnetic forces during the operation of the circuit interrupter 10, the center arc-horns S2 and 84 include the vertically extending lug portions 83 and 85 respectively which bear against the insulating washers 42 and 44 of the associated blowout coils 31 and 34, as best shown in FIG. 2. 'I'he terminal spacer members 39 disposed at the upper end of the blowout coils 31 and 34 also assist in maintaining said blowout coils in spaced relationship.

In order to facilitate the energization of the blowout coils 31 and 34 during the operation of the circuit interrupter 10, as will be described in detail hereinafter, the transfer arc-extinguishing section or stack 60 is disposed below the yoke portion 48 of the magnetic structure 40 and between the center arc-horns 82 and 84, as best shown in FIG. 1. The transfer arc-extinguishing section 60 includes a plurality of spaced, slotted, refractory plates, which may be formed from a ceramic material. The plates 61 may be spaced from one another by pairs of suitable spacers formed from a suitable material, such as asbestos rope, which are cemented or bonded between the plate 61 adjacent to the outer edges thereof to dene a plurality of vertically extending passages between said plates. As disclosed in detail in the Dickinson et al. patent previously mentioned, each of the plates 61 includes a vertically extending slot with the upper closed end of the slot being offset or displaced from the vertical center line of the plate. The plates 61 are assembled with the slots being alternately disposed on opposite sides of the vertical center line of the plates to provide a zig-zag arc passage in the arc-extinguishing section 60 when the arc established by the contact means 20 moves upwardly into the transfer arc-extinguishing section 60. As previously mentioned, the transfer arc-extinguishing section 66 is supported and positioned by the recesses 154 provided in the adjacent side wall portions 49 of the housing sections 32A and 32B as shown in FIG. 6. It is to be noted that the upper ends of the plates 61 which make up the arcextinguishing section 60 may be notched and interposed between the insulating washers 42 and 44 to assist in maintaining the lower portions of the blowout coils 31 and 34 in spaced relationship during the operation of the circuit interrupter 11B. It is to be noted that in the construction of the arc-chute .structure 30, two venting passages 50 .are provided on opposite sides of the yoke portion 48 of the magnetic structure 40 between the insulating washers 42 and 44 and between the center arc-horns 82 and 84 (as best shown in FIG. 2) to define two vertically extending gas passages which permit the escape of any arc gases generated in the transfer arc-extinguishing section 64B during the operation of the circuit interrupter 1t) conducting spacer block 16S on without passing through the arc-extinguishing sections 22 and 24.

Each of the main arc-extinguishing sections or stacks 22 and 24 includes a plurality of spaced, slotted refractory plates which may |be formed from a ceramic material, as shown in FIGS. l and 2. The refractory plates '76 are spaced from each other by narraw spacing strips or members 78 which are formed from a suitable material, such as asbestos rope, and cemented or bonded to the associated plates 76 at the outer edges thereof to dene a plurality of upwardly extending passageways 77 between said plates as best shown in FIG. 2. Each of the plates 76 has a closed upwardly extending slot which is displaced or offset with respect to the vertical centerline of the plate, as disclosed in detail in the Dickinson et al. patent previously mentioned. The plates 76 are assembled with the closed upper ends of the slots provided in the plates being offset on opposite sides of the centerline of the plates in the successive plates alternately to provide a zig-zag or serpentine arc passage through each of the arc-extinguishing sections 22 and 24. The arcextinguishing sections 22 and 24 are supported within the housing sections 32A and 32B on top of the rib portions 131 through 138 and also retained in position within said housing sections by the retaining portions 34 through 3S which are preferably formed integrally with the side wall portion 49 of said housing section, as previously described. It is to be noted that the arc-extinguishing sections 22 and 24 are spaced from the adjacent end wall portions 43 and 41, respectively, of the housing sections 32A and 32B by the retaining portions 35 and 38, respectively, with the outer arc-horns 92 and 94, respectively, being interposed between the arcextinguishing sections 22 and 24, respectively, and the adjacent end wall sections 43 and 41, respectively, of said housing sections. It is also to be noted that a venting passage is provided around each of the outer arc-horns which extends upwardly lbetween the end wall portions of the housing sections 32A and 32B and the adjacent arc-extinguishing sections 22 and 24 to permit the es- Cape of certain arc gases which may be generated during the operation of the circuit interrupter 10.

The outer arc-horn 92 may be secured to the adjacent end wall portions 43 of the housing sections 32A and 32B by any suitable means, such as the machine screws 116, which may be captured or retained by suitable recesses provided in the mating end wall portions 43 when said housing sections are assembled together. The outer arc-horn 92 is electrically connected to the movable contact 14 of the contact means 20 through the contact arm 16 by suitable conducting means, as indicated in FIG. l. Similarly, the outer arc-horn 94 is secured to the end wall portions 41 of the housing sections 32A and 32B by suitable lrneans, such as the machine screws 114, which are captured or retained in suitable recesses provided in the end wall portion 41 of the mating housing sections when said housing sections are assemblied together, as shown in FIG. l. The outer arc-horn 94 is electrically connected to the stationary contact portion 12A of the contact means 2t) by the conducing bolts 174 which extends through the end wall portion 41 and a which is mounted the conducting leaf springs 172 which bear against the conducting hinge pin 164 to `form a conducting path to the stationary contact portion 12A through the supporting 'brackets 162 which are also formed of a conducting material and which are electrically connected to the stationary contact portion 12A. The hinged contact joint just described forms a current path which is maintained while permitting rotation of the arc-chute structure 3i) about the hinge pin 164.

It is important to note that the construction of the housing sections 32A and 32B of the arc-chute structure 3() facilitates the assembly of the various parts of the a-rc-chute structure within the lhousing sections 32A and 32B, since the retaining and supporting portions which are formed integrally with the housing sections 32A and 32B readily receive the arc-extinguishing sections 22 and 24, which are normally preassembled before assembly with said housing sections, as well as the yblowout coils 31 and 34 and the associated center arc-horns 82 and 84, which are also normally preassemblied as a group. In order to facilitate assembly of the center archorns with the housing sections 32A and 32B, the upper end of each of the center arc-horns S2 and 84 includes a shoulder portion at each side thereof which projects into the rectangular opening 152 in each of the housing sections 32A and 32B to assist in maintaining the blowout coils 31 and 34, as well as the center arc-horn 82 and 84 in proper assembled relationship with the associated housing sections. The rectangular opening 152 in each of the side wall portions 49 of the housing sections 32A and 32B includes the smaller recesses 153 at the top and bottom thereof to receive the connecting bolts 102 and 104 to thereby assist in positioning the magnet structure 40 as well as the blowout coils 31 and 34 within the housing sections 32A and 32B. In addition, as previously mentioned the recesses 154 provided in the housing sections 32A and 32B position and retain the transfer arcextinguishing section 60 in proper assembled relation with the other parts of the arc-chute structure 30.

In the overall operation of the circuit interrupter 10, when the movable contact 14 first moves toward the left as viewed in FIG. 1, when the contact arm 16 is actuated by an associated operating mechanism (not shown), an arc is established between the movable contact 14 and the stationary contact portion 12A and 12B. The arc which is established is affected by the depending pole plate portions 47 of the magnetic structure 40 and imoves upwardly into engagement with the center or transfer arc-horns 82 and 84. Among the forces causing the arc which is established to move upwardly are those resulting from the loop effect which is produced by the current path which includes the two terminal conductors L1 and L2 and the contact arm 16. Other Iforces tending to cause the arc to move upwardly include those resulting from the thermal conditions produced by the heating of the air or gases by the arc and the consequent convection of such air or gases which tends to carry the arc upwardly towards the arc-extinguishing sections 22 and 24. As previously mentioned, the rib portions 131 through 138 and the intervening valley portions which are provided on each of the adjacent housing sections 32A and 32B increase the upward velocity of the arc which is established by producing a plurality of air or gas columns which are spaced from one another and which lengthen the arc which is established more quickly both in a radial direction and in a vertical direction. The upward movement of the arc is also accelerated by the rib portions 131 through 138 since the generally vertical valley portions between said rib portions function to permit gas to move in behind the arc as it moves upwardly and substantially overcome any vacuum which might otherwise tend to be produced behind the arc and retard its velocity as the arc moves upwardly.

The increase in the mobility of the arc is due to the dynamic gas pressure conditions which occur during an arc interrupting operation. During an are interruption, when an arc is initially established between the separable contacts, the arc heats up whatever gases are originally present or evolved to substantially increase the pressure of the mass of gas which is confined or restricted at least to a degree inside the arc chute housing adjacent to the contacts which are separating during arc interruption. The rib portions 131 through 138` function as spaced gas bale plates to cause the gas pressure which results during an arc interruption to increase the speed of movement of the arc between the separating contacts toward the arc-extinguishing means which are spaced from the contacts. In particular, since the rib portions 131 through 138 on the opposite sides of the arc are diverging in a direction away `from the contacts, the pressure of the gases present will react against the surfaces of the rib portions behind the arc to effectively maintain the gas pressure behind the moving arc, While the gas in front of the arc is permitted to expand in a direction away from the arc to thereby reduce the gas pressure in front of the arc. This reduction in gas pressure in front of the arc results because the sizes of the gas passage-ways in front of the arc are gradually increasing in a direction away from the contacts. In effect, during the initial movement of the arc between the separating contacts, the gas pressure which results due to the energy which is being transferred from the arc to the adjacent gas mass during interruption is subdivided and directed to accelerate the movement of the arc toward the arc-extinguishing means.

When the movable contact 14 reaches the position indicated in phantom at 14 in FIG. 1 and the arc which is established has moved upwardly to engage the center archorns 82 and 84, the arc is broken up into three portions 9A, 9B and 9C. The first arc portion 9A extends between the movable contact 14 and t-he center arc-horn 82. The second arc portion 9B extends between the center archorn 82 and the center arc-horn 84, while the third arc portion 9C extends between the stationary contact portion 12A and the center arc-horn 84. The second arc portion 9B is interrupted within the transfer arc-extinguishing section 6d to thereby energize the serially connected blowout coils 31 and 34 and to thereby provide a transverse magnetic field across or between the side pole plates 46, as indicated in FIG. 2 by the arrows 23 which accelerates the upward movement of the respective arc portions into the arc-extinguishig sections 22 and 24.

As the movable contact 14 moves farther toward the left as viewed in FIG. l and the arc portions 9A and 9C are rapidly drawn upwardly into the arc-extinguishing sections 22 and 24, respectively, the left-hand end of the arc portion 9A transfers to the arc-horn 92 and the right-hand end of the arc portion 9C transfers to the outer arc-horn 94. It is to be noted at this time that a current path through the circuit interrupter 10 extends from the line conductor L2 through the outer arc-horn 92, through the arc portion 9A after it transfers to the outer arc-horn 92, through the center arc-horn 82, the blowout coils 31 and 34, which are connected in series, the center arc-horn 84, through the arc portion 9C after it transfers to the outer arc-horn 94, through the outer arc-horn 94 the connecting bolts 17 4, the conducting spring spacer block 168, the leaf-springs 172, the hinge pin 174, the bracket members 162 and through the stationary contact portion 12A to the conductor L1. Each of the arc portions 9A and 9Crises upwardly within the arc-extinguishing sections 22 and 24, respectively, at substantially the same rate of speed and is forced upwardly within the zig-zag arc passages provided through the refractory plates of the respective arc-extinguishing sections. The arc portions 9A and 9C are quickly extinguished at the upper ends of the closed slots provided in the plate 76 of the arcextinguishing sections 22 and 24 and the circuit just described which extends through the circuit interrupter 10 is thereby broken or interrupted.

The apparatus embodying the teachings of this invention has several advantages. For example, the arc-chute housing construction as disclosed including the diverging spaced rib portions 131 through 138 has been found to have an increased interrupting ability or rating compared with conventional interrupter structures employing a flat arc shield or fire plate at the entrance to the associated arc-extinguishing structures. In addition, the insulating creepage path encountered by the arc as it moves upwardly from the contact means 20 towards the arc-extinguishing structures 22 and 24 is gradually increased and the velocity of arc movement has been found to be increased compared with conventional interrupter structures employing known arc shield structures. The assembly of the arc-chute structure 30 formed as disclosed has also been rfound to be facilitated compared with known arc-chute structures. The arc-chute housing construction as disclosed also promotes the cooling of the arc as it moves upwardly from the contact means 20 toward the arc-extinguishing structures 22 and 24 to thereby assist in deionizing the gases produced by the arc which is established.

It is to be understood that the teachings of the applicants invention may be applied to arc-chute structures employing an interleaved 1in construction such as disclosed in detail in U.S. Patent 2,442,199 which issued May 25, 1948, to Robert C. Dickinson and Russell E. Frink which is assigned to the same assignee as the present application, and to other types of arc-chute structures such as those disclosed in detail in U.S. Patent 2,889,433 which issued June 2, 1959, to John M. Kozlovic and Russell E. Frink which is assigned to the same assignee as the present application.

Since numerous changes may be made in the abovedescribed apparat-us and dilferent embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all the matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I vclaim as my invention:

1. A circuit interrupter comprising contact means actuable along a predetermined path between closed and open positions to establish an arc, an arc-chute having a housing in which the arc is extinguished, said housing including spaced side wall portions disposed on opposite sides of said contact means, and means for extinguishing said arc disposed inside said housing and spaced from and above said contact means, each of said side Wall portions including a plurality of generally vertical, integral spaced rib portions projecting laterally toward said contact means and extending from immediately adjacent said contact means to said arc-extinguishing means to define a lengthened creepage path for the arc and a plurality of gas passages adjacent to each side wall portion and extending generally vertically away from said contact means, said rib portions being generally diver-ging with respect to one another in a direction away from said contact means, said rib portions being disposed generally transversely to the predetermined path of said contact means and at least along the initial portion of said path from the closed position of said contact means, the size of each of said gas passages between said spaced rib portions gradually increasing in a direction toward said `arc extinguishing means to cause the gas pressure which results during interruption to increase the speed of the arc toward the arc extinguishing means.

2. A circuit interrupter comprising contact means actuable along a predetermined path between closed and open positions for establishing an arc, an arc-chute structure including a pair of spaced side wall portions formed from anti-tracking, insulating material and a plurality of spaced, substantially parallel, plates of insulating material spaced from said contact means and disposed to extend bet-Ween said side wall portions to receive said arc and to cause its extinction, each of said wall portions including a plurality of spaced, integral, raised portions projecting laterally toward said contact means and extending from a point immediately adjacent said contact means to a point adjacent said plates, said raised portions being generally diverging with respect to one another in a direction away from said contact means, said raised portions being disposed generally transversely to the predetermined path of said contact means and spaced along at least the initial portion of said path from the closed position of said contacts, and said raised portions forming a lengthened creepage path for the arc and defining a plurality of gas passages therebetween which are gradually increasing in size in a direction toward said plates to cause the gas pressure which results during interruption to increase the speed of the arc toward the plates.

y3. A circuit interrupter comprising contact means including a relatively stationary contact and a movable contact, said movable contact being separable from said stationary contact along a predetermined path between closed and open positions with respect to said stationary contact to establish an arc, a generally rectangular arc-chute including spaced side wall portions and connecting end portions, a plurality of spaced, substantially parallel, insulating plates spaced from said contact means and extending -between said side wall portions to receive and to extinguish said arc, means for effecting movement of said arc into said plates when said movable contact is separated from said stationary contact, and a plurality of spaced partition members formed integrally with each side wall portion to project laterally toward said contact means and to extend from immediately adjacent said contact means to said plates, said partition members being generally diverging with respect to one another in a direction away from the contact means, said partition members being disposed generally transversely to the predetermined path ot said movable contact and spaced along at least the initial portion of the path from the closed position of the movable contact with respect to the stationary contact, and said partition members forming a lengthened creepage path for the arc and dening a pl-urality of gas passages therebetween which are gradually increasing in size in a direction toward said plates to cause the gas pressure which results during interruption to increase the speed of the arc toward the plates, one end of each of said partition members bearing against said plates to assist in supporting and retaining said plates in position.

4. A circuit interrupter comprising contact means including a relatively stationary contact and a movable contact, said movable contact being separable from said stationary contact along a predetermined path between closed and open positions with respect to said stationary contact to establish an arc, a generally rectangular arc-chute including spaced side wall portions and connecting end portions, a plurality of generally vertical, substantially parallel, spaced, insulating plates spaced from and disposed above said contact means and extending between said side wall portions to receive said arc and to extinguish said arc, means for elfecting movement of said arc into said plates when said movable contact is separated from said stationary contact, and a plurality of spaced partition members formed integrally with each side wall portion to project laterally toward said contact means and to extend generally vertically from immediately adjacent to said contact means to said plates, said partition members being generally diverging with respect to one another in a direction away from said contact means, said partition members being generally diverging with respect to one another in a direction away from the contact means, said partition members being disposed generally transversely to the predetermined path of said movable contact and spaced along at least the initial portion of the path from the closed position of the movable contact with respect to the stationary contact, and said partition members forming a lengthened creepage path for the arc and defining a plurality of gas passages therebetween which are gradually increasing in size in a direction toward said plates to cause the gas pressure which results during interruption to increase the speed of the arc toward the plates.

5. A circuit interrupter comprising contact means actuable along a predetermined path between closed and open positions to establish an arc, a housing in which the arc is moved having spaced side walls, one or more blowout coils disposed in the housing to effect motion of the arc, a magnetic core passing through said blowout coils and said side walls, a pair of arc-extinguishing structures disposed inside said housing on opposite sides of said core and spaced from said contact means, each of said walls including a plurality of generally vertical, integral,

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alternate valley and rib portions which project laterally inwardly toward said contact means and which extend from immediately adjacent said contact means to said arcextinguishing structures to said rib portions of said side Walls being relatively diverging in a direction away from said contact means said rib portions being disposed generally transversely to the predetermined path of said contact means and at least along the initial portion of said path from the closed position of said contact means, and said rib portions forming a lengthened creepage path for the arc and dening a plurality of gas passages therebetween which are gradually increasing in a direction toward said arc-extinguishing structures to cause the gas pressure i2 which results during interruption to increase the speed of the arc toward the arc-extinguishing structures.

References Cited by the Examiner UNITED STATES PATENTS 10 ROBERT K. SCHAEFER, Primm Examiner.

K, H. CLAFFY, P. E. CRAWFORD, R. S. MACON,

Assistant Examiners. 

1. A CIRCUIT INTERRUPTER COMPRISING CONTACT MEANS ACTUABLE ALONG A PREDETERMINED PATH BETWEEN CLOSED AND OPEN POSITIONS TO ESTABLISH AN ARC, AN ARC-CHUTE HAVING A HOUSING IN WHICH THE ARC IS EXTINGUISHED, SAID HOUSING INCLUDING SPACED SIDE WALL PORTIONS DISPOSED ON OPPOSITE SIDES OF SAID CONTACT MEANS, AND MEANS FOR EXTINGUISHING SAID ARC DISPOSED INSIDE SAID HOUSING AND SPACED FROM AND ABOVE SAID CONTACT MEANS, EACH OF SAID SIDE WALL PORTIONS INCLUDING A PLURALITY OF GENERALLY VERTICAL, INTEGRAL SPACED RIB PORTIONS PROJECTING LATERALLY TOWARD SAID CONTACT MEANS AND EXTENDING FROM IMMEDIATELY ADJACENT SAID CONTACT MEANS TO SAID ARC-EXTINGUISHING MEANS TO DEFINE A LENGTHENED CREEPAGE PATH FOR THE ARC AND A PLURALITY OF GAS PASSAGES ADJACENT TO EACH SIDE WALL PORTION AND EXTENDING GENERALLY VERTICALLY AWAY FROM SAID CONTACT MEANS, SAID RIB PORTIONS BEING GENERALLY DIVERGING WITH RESPECT TO ONE ANOTHER IN A DIRECTION AWAY FROM SAID CONTACT MEANS, SAID RIB PORTIONS BEING DISPOSED GENERALLY TRANSVERSELY TO THE PREDETERMINED PATH OF SAID CONTACT MEANS AND AT LEAST ALONG THE INITIAL PORTION OF SAID PATH FROM THE CLOSED POSITION OF SAID CONTACT MEANS, THE SIZE OF EACH OF SAID GAS PASSAGES BETWEEN SAID SPACED RIB PORTIONS GRADUALLY INCREASING IN A DIRECTION TOWARD SAID ARC EXTINGUISHING MEANS TO CAUSE THE GAS PRESSURE WHICH RESULTS DURING INTERRUPTION TO INCREASE THE SPEED OF THE ARC TOWARD THE ARC EXTINGUISHING MEANS. 